There are other buttons that give me issues as well, but with the options button in particular, I have to close the Mumu app and open it up again to fix it. Sometimes, that doesn't even do anything.
#Sometimes, my PS5 controller's options button stops working?
twin tiger
radiant valley
Kinda late to the party but had that issue aswell. Happening after you opened the chat. If you load to another map it's fixed in my case, but probably not the solution you were hoping for.